This. If downtime is that big of an issue, you should be on Cloudflare's business/enterprise plan which allows CNAME DNS, have redundant DNS providers with 30s

This. If downtime is that big of an issue, you should be on Cloudflare's business/enterprise plan which allows CNAME DNS, have redundant DNS providers with 30s TTLs that flip over to another provider. Better yet if you can 50/50 the traffic and 100/0 it when something goes bad. Downside is cost and DNSSEC has an issue with multiple keys. I think there was an RFC on that though I'm not sure it's well supported yet.